decryptFile method

Future<PqStreamingHeader> decryptFile({ required Uint8List recipientSecretKey, required File input, required File output, Uint8List? recipientKexSecretKey, String? recipientKeyId, Uint8List? signerPublicKey, Uint8List? aadResolver(PqStreamingHeader header)?, })

Streams a .pqfs input back to plaintext at output in bounded memory.

aadResolver builds the expected AAD from the (now header-bound) metadata, mirroring the recipe binding of the one-shot path. On any failure — a bad signature, AAD mismatch, tampered/reordered/truncated frame — the partial output is removed before the error propagates.

Implementation

Future<PqStreamingHeader> decryptFile({
  required Uint8List recipientSecretKey,
  required File input,
  required File output,
  Uint8List? recipientKexSecretKey,
  String? recipientKeyId,
  Uint8List? signerPublicKey,
  Uint8List? Function(PqStreamingHeader header)? aadResolver,
}) async {
  await output.parent.create(recursive: true);
  final sink = await output.open(mode: FileMode.write);
  PqStreamingHeader? header;
  var success = false;
  try {
    final frames = decryptStream(
      recipientSecretKey: recipientSecretKey,
      recipientKexSecretKey: recipientKexSecretKey,
      recipientKeyId: recipientKeyId,
      input: input,
      signerPublicKey: signerPublicKey,
      aadResolver: aadResolver,
      onHeader: (h) => header = h,
    );
    await for (final plaintext in frames) {
      if (plaintext.isNotEmpty) await sink.writeFrom(plaintext);
    }
    await sink.flush();
    success = true;
    return header!;
  } finally {
    await sink.close();
    if (!success) await _deleteQuietly(output);
  }
}